With the 1.7.0 update, the improved color contrast of the text labels was introduced to improve accessibility, which is pretty cool, and finally I could get rid of a lot of CSS rules to manually adjust each label, today while removing some of those rules I came across the ones I use to change the icon color in groups with light backgrounds, which is exactly why I thought that now that this system is included in Flarum it would be a good idea to use it for group badges.
I haven't made an issue about this in the Flarum repo because I don't think it qualifies as a bug(?), but if I'm wrong and it does, I'd have no problem creating an issue to track it, just let me know.